Constitutive Model Development for Thermo-Mechanical Fatigue Response Simulation of Haynes 230

2012 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Mamballykalathil Menon ◽  
Tasnim Hassan
Keyword(s):  
Stress Response ◽  
Constitutive Model ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Large Set ◽  
Mean Stress ◽  
Liner Material ◽  
Mechanical Fatigue ◽  
Combustor Liner ◽  
Mean Strain

Turbine engine combustor components are subject to thermo-mechanical fatigue (TMF) during service. The combustor liner temperatures can sometimes reach as high as 1800°F. An accurate estimate of the strains at critical locations in the combustor liner is required for reliable lifing predictions. This demands the need for a detailed analysis of the TMF responses and a robust constitutive model capable of predicting the same. A large set of experiments have been carried out on the liner material, a nickel based alloy, HA 230, in an effort to understand its thermo-mechanical fatigue constitutive response. The out-of-phase strain-controlled TMF experiments with a negative mean strain show a positive mean stress response, while the in-phase TMF experiments with a positive mean strain show a negative mean stress response. A Chaboche based viscoplastic constitutive model is under development. It will have several essential features such as nonlinear kinematic hardening, isotropic hardening, strain range dependence, rate dependence, temperature dependence and static recovery. The constitutive model being developed for accurately calculating the stress-strain response is being carried out with the final objective of predicting the strains in an actual combustor liner in service through finite element simulation for fatigue lifing.

Out-of-Phase and In-Phase Thermo-Mechanical Fatigue Response Simulations of Haynes 230

2014 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Paul R. Barrett ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Gas Turbines ◽  
Rate Dependence ◽  
Maximum Temperature ◽  
Large Set ◽  
Mean Stress ◽  
Stress Evolution ◽  
Haynes 230 ◽  
Mechanical Fatigue

Temperatures at critical locations in propulsion turbine engine combustor components can be as high as 982°C (1800°F). High temperature thermal gradients, and start-up and shut-down operations of gas turbines, induce thermo-mechanical fatigue (TMF) failure. Dwell periods at high temperatures accompanied by repeated loading cycles, eventually lead to failure of the components through creep-fatigue processes. In an effort to decipher the complex high temperature phenomena, a large set of isothermal and thermo-mechanical fatigue experiments have been carried out on the gas turbine combustor liner material, Haynes 230. The out-of-phase strain-controlled TMF experiments with compressive peak hold result in mean stress evolution in the tensile direction, whereas the in-phase TMF experiments with tensile peak hold result in mean stress evolution in the compressive direction. Experimental results indicate that the maximum temperature in the loading cycle influences the material property evolution with cycle. A unified viscoplastic constitutive model based on the Chaboche type nonlinear kinematic hardening rule was developed, including the added features of strain range dependence, rate dependence, temperature rate dependence, static recovery, mean stress evolution, and maximum temperature influence. The new constitutive model was validated against stress-strain responses of Haynes 230 under TMF loading. Paper published with permission.

Constitutive Modeling of Haynes 230 for Anisothermal Thermo-Mechanical Fatigue and Multiaxial Creep-Ratcheting Responses

2013 ◽  
Author(s):  
Raasheduddin Ahmed ◽  
Paul R. Barrett ◽  
Tasnim Hassan
Keyword(s):  
High Temperature ◽  
Constitutive Model ◽  
Structural Integrity ◽  
Kinematic Hardening ◽  
Critical Evaluation ◽  
Accurate Estimation ◽  
Nickel Base Superalloy ◽  
Haynes 230 ◽  
Analysis And Design ◽  
Mechanical Fatigue

Service life analysis and design of high temperature components, such as turbine engines, needs accurate estimation of stresses and strains at failure locations. The structural integrity under these high temperature environments can be evaluated through finite element structural analysis. This requires a robust constitutive model to predict local stresses and strains. A unified viscoplastic constitutive model based on the Chaboche type nonlinear kinematic hardening rule was developed including the added features of strain range dependence, rate dependence, temperature dependence, static recovery, and a mean stress evolution. The new constitutive model was validated through critical evaluation of the simulation of a broad set of stress and strain responses of a nickel-base superalloy Haynes 230. The experimental database encompasses uniaxial strain-controlled loading histories which include isothermal low cycle creep-fatigue and anisothermal thermo-mechanical fatigue experiments at temperatures ranging from 75°F to 1800°F. Simulations from the modified model are presented to demonstrate its strengths and weaknesses, and future work is needed for developing a robust constitutive model.

Ratcheting of Stainless Steel 304 Under Multiaxial Nonproportional Loading

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Kwang S. Kim ◽  
Rong Jiao ◽  
Xu Chen ◽  
Masao Sakane
Keyword(s):  
Stainless Steel ◽  
Shear Stress ◽  
Kinematic Hardening ◽  
Isotropic Hardening ◽  
Mean Stress ◽  
Nonproportional Loading ◽  
Torsional Strain ◽  
Ratcheting Strain ◽  
Stainless Steel 304 ◽  
Strain Cycling

Multiaxial ratcheting is often simulated by use of nonlinear kinematic hardening models, while in reality materials show cyclic hardening/softening and additional hardening under nonproportional loading. The effect of isotropic hardening on ratcheting needs to be addressed in simulation. In this study, ratcheting tests are conducted on stainless steel 304 under uniaxial, torsional, and combined axial-torsional loading. The ratcheting strain is predicted based on the constitutive theory that incorporates a modified Ohno–Wang kinematic hardening rule and Tanaka’s isotropic hardening model. The results show that the main features of the stress-strain response can be simulated with the constitutive model. Ratcheting strain under axial mean stress depends highly on the loading path and load level, and the degree of cyclic changes in shear stress under torsional strain control is not as influential. The torsional ratcheting strain under mean shear stress with (or without) fully reversed axial strain cycling is found close to the axial ratcheting strain under equivalent mean stress with (or without) torsional strain cycling. In all, the experimental and predicted ratcheting strains for nonproportional paths are found in decent correlation. However, overprediction still prevails for some loading paths, and ratcheting rates deviate considerably from experimental values.

Comparison of Different Constitutive Models in Sheet Metal Forming

2013 ◽  
Vol 554-557 ◽  
pp. 1203-1216 ◽  
Author(s):  
Meriç Uçan ◽  
Haluk Darendeliler
Keyword(s):  
Constitutive Model ◽  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Kinematic Hardening ◽  
Piecewise Linear ◽  
Constitutive Models ◽  
Isotropic Hardening ◽  
Anisotropic Plasticity ◽  
Elastic Plastic

The effects of different constitutive models in sheet metal forming are investigated by considering the cylindrical and square cup drawing and V-bending processes. Numerical analyses are performed by employing eight different constitutive models. These are elastic plastic constitutive model with isotropic hardening, elastic plastic constitutive model with kinematic hardening, elastic plastic constitutive model with combined hardening, power law isotropic plasticity, piecewise linear isotropic plasticity, three-parameter Barlat, anisotropic plasticity and transversely anisotropic elastic plastic models. The simulations are performed for three different materials, St12 steel, Al-5182 aluminum and stainless steel 409 Ni, by using a commercial finite element code. A number of experiments are carried out and the experimental and analytical results are utilized to evaluate the results of simulations.

Analytical Solutions for Circular Bars Subjected to Large Strain Plastic Torsion

1990 ◽  
Vol 57 (2) ◽  
pp. 298-306 ◽  
Author(s):  
K. W. Neale ◽  
S. C. Shrivastava
Keyword(s):  
Closed Form ◽  
Analytical Solutions ◽  
Large Strain ◽  
Kinematic Hardening ◽  
Flow Theory ◽  
Constitutive Laws ◽  
Isotropic Hardening ◽  
Large Strains ◽  
Inelastic Behavior ◽  
Rate Dependent

The inelastic behavior of solid circular bars twisted to arbitrarily large strains is considered. Various phenomenological constitutive laws currently employed to model finite strain inelastic behavior are shown to lead to closed-form analytical solutions for torsion. These include rate-independent elastic-plastic isotropic hardening J2 flow theory of plasticity, various kinematic hardening models of flow theory, and both hypoelastic and hyperelastic formulations of J2 deformation theory. Certain rate-dependent inelastic laws, including creep and strain-rate sensitivity models, also permit the development of closed-form solutions. The derivation of these solutions is presented as well as numerous applications to a wide variety of time-independent and rate-dependent plastic constitutive laws.

scholarly journals Finite Plane Strain Bending under Tension of Isotropic and Kinematic Hardening Sheets

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1166
Author(s):  
Stanislav Strashnov ◽  
Sergei Alexandrov ◽  
Lihui Lang
Keyword(s):  
Plane Strain ◽  
Kinematic Hardening ◽  
Tensile Force ◽  
Plastic Region ◽  
Equivalent Plastic Strain ◽  
Isotropic Hardening ◽  
Finite Plane ◽  
Present Solution ◽  
Bending Under Tension ◽  
Elastic Unloading

The present paper provides a semianalytic solution for finite plane strain bending under tension of an incompressible elastic/plastic sheet using a material model that combines isotropic and kinematic hardening. A numerical treatment is only necessary to solve transcendental equations and evaluate ordinary integrals. An arbitrary function of the equivalent plastic strain controls isotropic hardening, and Prager’s law describes kinematic hardening. In general, the sheet consists of one elastic and two plastic regions. The solution is valid if the size of each plastic region increases. Parameters involved in the constitutive equations determine which of the plastic regions reaches its maximum size. The thickness of the elastic region is quite narrow when the present solution breaks down. Elastic unloading is also considered. A numerical example illustrates the general solution assuming that the tensile force is given, including pure bending as a particular case. This numerical solution demonstrates a significant effect of the parameter involved in Prager’s law on the bending moment and the distribution of stresses at loading, but a small effect on the distribution of residual stresses after unloading. This parameter also affects the range of validity of the solution that predicts purely elastic unloading.

Pertinence of the Grain Size on the Mechanical Strength of Polycrystalline Metals

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
N. A. Zontsika ◽  
A. Abdul-Latif ◽  
S. Ramtani
Keyword(s):  
Grain Size ◽  
Mechanical Strength ◽  
Kinematic Hardening ◽  
Uniaxial Stress ◽  
Isotropic Hardening ◽  
Ultrafine Grained ◽  
Consistent Model ◽  
Micromechanical Approach ◽  
Interaction Law ◽  
Small Deformations

Motivated by the already developed micromechanical approach (Abdul-Latif et al., 2002, “Elasto-Inelastic Self-Consistent Model for Polycrystals,” ASME J. Appl. Mech., 69(3), pp. 309–316.), a new extension is proposed for describing the mechanical strength of ultrafine-grained (ufg) materials whose grain sizes, d, lie in the approximate range of 100 nm < d < 1000 nm as well as for the nanocrystalline (nc) materials characterized by d≤100 nm. In fact, the dislocation kinematics approach is considered for characterizing these materials where grain boundary is taken into account by a thermal diffusion concept. The used model deals with a soft nonincremental inclusion/matrix interaction law. The overall kinematic hardening effect is described naturally by the interaction law. Within the framework of small deformations hypothesis, the elastic part, assumed to be uniform and isotropic, is evaluated at the granular level. The heterogeneous inelastic part of deformation is locally determined. In addition, the intragranular isotropic hardening is modeled based on the interaction between the activated slip systems within the same grain. Affected by the grain size, the mechanical behavior of the ufg as well as the nc materials is fairly well described. This development is validated through several uniaxial stress–strain experimental results of copper and nickel.

Calibration and Validation of an Elasto-Viscoplastic Material Model for a Hot Work Tool Steel Used in Pressure Casting Dies

2007 ◽  
Vol 345-346 ◽  
pp. 685-688 ◽  
Author(s):  
Werner Ecker ◽  
Thomas Antretter ◽  
R. Ebner
Keyword(s):  
Constitutive Model ◽  
Tool Steel ◽  
Mechanical Response ◽  
Mechanical Load ◽  
Kinematic Hardening ◽  
Ex Situ ◽  
Pressure Casting ◽  
Viscoplastic Material ◽  
Crack Network ◽  
Hot Work Tool Steel

Pressure casting dies are subjected to a large number of thermal as well as mechanical load cycles, which are leading to a characteristic thermally induced crack network on the die surface. As a typical representative for a die material the cyclic thermo-mechanical behavior of the hot work tool steel grade 1.2343 (X38CrMoV5-1) is investigated both experimentally as well as numerically. On the one hand the information from isothermal compression-tension tests is used in a subsequent analysis to calibrate a constitutive model that takes into account the characteristic combined isotropic-kinematic hardening/softening of the material. On the other hand the non-isothermal mechanical response of the material to thermal cycles is characterized by means of a periodic laser pulse applied to a small plate-like specimen which is cooled on the back. The residual stresses developing at the surface of the irradiated region of the specimen are determined ex-situ by means of X-ray diffraction. The obtained values agree well with the results of an accompanying finite-element study. This information is used to verify the calibrated constitutive model. The material law is finally used for the prediction of stresses and strains in a die.

Generation of Cyclic Stress-Strain Curves for Sheet Metals

2000 ◽  
Author(s):  
K. M. Zhao ◽  
J. K. Lee
Keyword(s):  
Constitutive Model ◽  
Kinematic Hardening ◽  
Optimization Procedure ◽  
High Strength ◽  
Cyclic Stress ◽  
Bending Moments ◽  
Sheet Metals ◽  
Stress Strain ◽  
Normal Anisotropy ◽  
Material Parameters

Abstract The main objective of this paper is to generate cyclic stress-strain curves for sheet metals so that the springback can be simulated accurately. Material parameters are identified by an inverse method within a selected constitutive model that represents the hardening behavior of materials subjected to a cyclic loading. Three-point bending tests are conducted on sheet steels (mild steel and high strength steel). Punch stroke, punch load, bending strain and bending angle are measured directly during the tests. Bending moments are then computed from these measured data. Bending moments are also calculated based on a constitutive model. Normal anisotropy and nonlinear isotropic/kinematic hardening are considered. Material parameters are identified by minimizing the normalized error between two bending moments. Micro genetic algorithm is used in the optimization procedure. Stress-strain curves are generated with the material parameters found in this way, which can be used with other plastic models.

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